Joined structure of main girder and concrete slab, and rejoining method of main girder and concrete slab

Abstract

To efficiently rejoin concrete slabs with a main girder that have been cut apart.SOLUTION: In a joined structure of a main girder and concrete slabs, in which the concrete slabs of a bridge that are cut apart from the main girder by cutting a joint are rejoined with the main girder, a shear key structure in the bridge axis direction and filling materials are provided between the cut surface on the main girder side and the cut surface on the concrete slab side at the joint.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The present invention relates to a composite structure of a bridge in which a concrete floor slab and a steel main girder are integrated, and a method for recombining the concrete floor slab separated from the main girder by cutting a joint portion with the main girder, and a method for recombining the main girder and the concrete floor slab.

Background Art

[0002] In order to perform renewal work of replacing an existing concrete floor slab installed on the main girder of a bridge with a new concrete floor slab, first, a separation work between the existing concrete floor slab and the main girder is performed, and the existing concrete floor slab is cut into a shape that can be loaded on a transport vehicle. After that, the existing concrete floor slab cut into a shape that can be loaded on a transport vehicle is removed. Next, a base treatment is performed to remove concrete pieces, anchor bars, stud dowels, etc. remaining on the upper surface of the main girder, and to remove rust and the like. After these operations are completed, an operation of installing a new concrete floor slab on the upper surface of the main girder that has been subjected to the base treatment is performed.

[0003] All of the above operations need to be carried out after imposing construction traffic regulations such as stopping the passage of general vehicles and various traffic restrictions. Among them, the existing concrete floor slab is firmly joined to the stud dowels and anchor bars provided on the upper surface of the main girder through the concrete. Therefore, the work of separating and removing the existing concrete floor slab and the main girder requires a particularly large amount of labor and time.

[0004] However, in heavy traffic roads in urban areas or mountainous areas sandwiched between long tunnels, implementing construction traffic regulations for a long period of time may have an adverse impact on the traffic environment in the surrounding areas. For this reason, a method is desired that can reduce the labor involved in these operations, shorten the period of implementing construction traffic regulations, and quickly implement renewal work. Under such circumstances, for example, Patent Document 1 discloses a method of performing an operation of cutting a joint portion between an existing concrete floor slab and a main girder, and providing a composite structure for joining the existing concrete floor slab separated by the cutting and the main girder behind it.

[0005] In this way, the existing concrete floor slab of the main girder can be recombined so that the bridge can function as a composite girder bridge. Therefore, during the period from the work of separating the existing concrete floor slab from the main girder to the start of the work of removing the existing concrete floor slab, the traffic opening period of general vehicles can be ensured without imposing restrictions on the running load or regulations on the driving lane.

Prior Art Documents

Patent Documents

[0006]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0007] The composite structure of Patent Document 1 installs a composite jig by using a cut surface formed by cutting the joint between the existing concrete floor slab and the main girder. In a structure that uses such a cut surface, when the width shape of the joint (length in the direction perpendicular to the bridge axis) is small and the composite jig cannot be installed, additional work is required to increase the width by ramming non-shrink mortar, etc., to secure the installation space for the composite jig. Thus, the installation of the composite jig required many work steps and was laborious.

[0008] In addition, the composite jig is manufactured with its shape adjusted according to the state of the mounting position for each site. For this reason, the manufacturing cost increases, and the composite jig removed to remove the existing concrete floor slab after recombining cannot be reused. Furthermore, it had various problems such as low horizontal shear strength, an increased installation quantity depending on site conditions, and on the other hand, a large overall shape of the composite jig and a heavy burden on workers during the installation work.

[0009] The present invention has been made in view of such problems, and its main object is to efficiently recombine the cut and separated concrete floor slab and the main girder.

Means for Solving the Problem

[0010] In order to achieve such an object, the composite structure of the main girder and the concrete floor slab of the present invention is a composite structure of the main girder and the concrete floor slab, which recombines the concrete floor slab of the bridge separated from the main girder by cutting the joint portion to the main girder, and a shear key structure in the bridge axis direction is provided between the cutting surface on the main girder side and the cutting surface on the concrete floor slab side at the joint portion.

[0011] The composite structure of the main girder and the concrete floor slab of the present invention is characterized in that the cutting surface on the main girder side and the cutting surface on the concrete floor slab side are formed in a wave shape that meshes with each other to form the shear key structure.

[0012] The composite structure of the main girder and the concrete floor slab of the present invention is characterized in that the wavelength of the wave shape is about 3 to 10 times the amplitude. The wave shape is not limited as long as it has a predetermined shear resistance, whether it is a single structure or a continuous structure, and it does not have to be a standing wave.

[0013] The composite structure of the main girder and the concrete floor slab of the present invention is characterized in that only a filler is provided between the cutting surface on the main girder side and the cutting surface on the concrete floor slab side, instead of a combination of the shear key structure and the filler.

[0014] The recombining method of the main girder and the concrete floor slab of the present invention is a recombining method of the main girder and the concrete floor slab, which recombines the concrete floor slab of the bridge separated from the main girder by cutting the joint portion to the main girder, and includes a step of cutting the joint portion so that the cutting surface on the main girder side and the cutting surface on the concrete floor slab side are in a wave shape, and a step of filling a filler between the cutting surface on the main girder side and the cutting surface on the concrete floor slab side.

[0015] According to the composite structure of the main girder and the concrete floor slab of the present invention and the method for recombining the main girder and the concrete floor slab, the shortage of the horizontal shear force in the bridge axis direction, which was borne by the anti-slip such as stud dowels provided on the upper surface of the main girder, caused by cutting the joint, can be compensated by the shear key structure in the bridge axis direction provided at the cut portion of this joint, the adhesive force of the filler, and the frictional force due to the self-weight of the floor slab.

[0016] Moreover, it can be formed by cutting the joint into a wave shape and making the cut surface on the main girder side and the cut surface on the concrete floor slab side into a wave shape that meshes with each other. Therefore, when recombining the existing concrete floor slab after cutting the joint to the main girder, the installation work of the composite jig, which was carried out, can be omitted, and the work efficiency can be greatly improved.

[0017] Furthermore, by filling a filler between the cut surfaces of the main girder side and the concrete floor slab side forming the shear key structure, it becomes possible to further reinforce the shear force in the bridge axis direction by utilizing the adhesive force between the cut surfaces. Note that if a predetermined shear resistance can be ensured, it is possible to join only with the adhesive force of the filler and the frictional force due to the self-weight of the floor slab.

Effect of the Invention

[0018] According to the present invention, by providing a shear key structure in the bridge axis direction at the cut portion of the joint, it becomes possible to efficiently recombine the cut and separated concrete floor slab and the main girder.

Brief Description of the Drawings

[0019]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Mode for Carrying Out the Invention

[0020] As shown in FIGS. 1(a) and 1(b), the bridge 200 includes a steel main girder 201 made of I-beam, a concrete slab 202 installed on the main girder 201, and a plurality of pairs of inclined structures 203 arranged at intervals in the bridge axis direction between the main girders 201 adjacent to each other in the direction perpendicular to the bridge axis. Further, a haunch portion 204 serving as a joint portion with the main girder 201 is formed on the lower surface of the concrete slab 202.

[0021] In the bridge 200 having the composite structure in which the concrete slab 202 and the steel main girder 201 are integrated, as a rough procedure for carrying out the slab replacement work, first, as shown in FIGS. 1(a) and 1(b), the haunch portion 204 forming the joint portion between the concrete slab 202 and the main girder 201 is horizontally cut along the upper surface of the main girder 201.

[0022] Next, as shown in FIG. 1(c), the concrete slab 202 cut and separated from the main girder 201 is cut in a substantially vertical direction along the bridge axis direction and the direction perpendicular to the bridge axis so as to have a size that can be loaded on a transport vehicle, and a plurality of slab pieces 205 are formed. After removing the slab pieces 205 thus formed by appropriate means, after performing necessary base treatment on the upper surface of the main girder 201 after removal, a new concrete slab is installed.

[0023] In the present embodiment, while proceeding with the cutting operation of the haunch portion 204, a composite structure 100 having a shear key structure 1 as shown in FIGS. 2 and 3 is formed between the cut and separated concrete slab 202 and the steel main girder 201. Thus, the concrete slab 202 and the main girder 201 are integrated, and their recombining is achieved.

[0024] Thus, during the period from the cutting operation of the haunch portion 204 to the start of the operation of forming a plurality of floor slab pieces 205 to remove the concrete floor slab 202, it is possible to provide a traffic liberation time zone in which general vehicles can be used on the bridge 200 in which the concrete floor slab 202 and the main girder 201 are recombined without restricting the running load or regulating the running lane.

[0025] ≪≪Synthetic Structure of Main Girder and Concrete Floor Slab≫≫ As shown in FIGS. 2 and 3(a), the synthetic structure 100 is composed of a shear key structure 1, a space retaining member 2, and a filling material 3.

[0026] ≪Shear Key Structure≫ The shear key structure 1 is formed by making the cut surface 204a on the main girder 201 side and the cut surface 204b on the concrete floor slab 202 side, which are formed when the haunch portion 204 is cut, into a wave shape that meshes with each other.

[0027] The wave shape is not limited in any way as long as it oscillates in the vertical direction and progresses in the bridge axis direction. For example, continuous shapes such as a sawtooth shape, a triangular wave shape, a sine wave shape, and a rectangular wave shape shown in FIGS. 4(a) to (d), or their single shapes, can be cited as examples. Also, the shear key may be intentionally created or may be accidentally formed during cutting.

[0028] Further, it is preferable to set the wavelength with respect to the amplitude (half of the wave height) of the wave shape as shown in FIG. 3(b) to be 5 times or more and 10 times or less. This is for the following reason. When adopting a synthetic structure that integrates a precast PC board and the cast-in-place concrete on its upper surface for the floor slab of a road bridge, it is known to provide an uneven shape with a wavelength with respect to the amplitude of about 10 times on the upper surface of the precast PC board.

[0029] In addition, when the road bridge is an arch bridge made of reinforced concrete, in order to reliably transmit the shear force, it is known to adopt a joint key structure with a wavelength about 3 to 5 times the amplitude for the joint part formed in the main girder of the precast concrete structure. On the other hand, in order to obtain a composite effect at the joint surface between the precast concrete slab and the in-situ concrete, it is known to adopt a joint key structure with a wave height about 10 times the amplitude. Considering these, the wavelength with respect to the amplitude of the waveform shape was set to about 3 to 10 times.

[0030] ≪Spatial Retainer and Filling Material≫ The space retaining material 2 is a member driven into the gap between the cut surface 204a on the main girder 201 side and the cut surface 204b on the concrete floor slab 202 side, and any material may be adopted as long as it does not deform under the load of the concrete floor slab 202. For example, wedge-shaped or rectangular blocks can be cited as examples. The arrangement position of the space retaining material 2 may be arranged on both sides sandwiching the web 201b of the main girder 201 when viewed from the bridge axis direction according to the shape and width of the gap, or may be arranged on only one side.

[0031] The filling material 3 is filled in the gap between the cut surface 204a on the main girder 201 side and the cut surface 204b on the concrete floor slab 202 side, the height direction interval of which is maintained by the space retaining material 2. In this embodiment, non-shrink mortar is adopted for the filling material 3, but it is not limited thereto. Any material may be used as long as it is excellent in transmitting compressive force and shear force and is easy to peel off when the concrete floor slab 202 is removed after recombining. For example, cement milk, epoxy resin, etc. can be cited as examples.

[0032] When the hunch part 204 is cut and there is a shortage even when the vehicle passes on the road formed on the concrete floor slab 202, which was borne by the stud gib 201c, concrete, etc. provided on the upper surface of the main girder 201 as shown in Fig. 5(a), and the shortage occurs due to the shear force in the bridge axis direction generated at that time, this shortage can be reinforced by the shear key structure 1 and the frictional force due to the self-weight of the concrete floor slab 202.

[0033] Also, by filling the gap between the cut surface 204a on the main girder 201 side and the cut surface 204b on the concrete floor slab 202 side with the filler 3, it is possible to further reinforce the shear force in the bridge axis direction by utilizing the adhesive force between the cut surfaces 204a and 204b.

[0034] Furthermore, even when the compressive force and vertical force in the bridge axis direction generated when the vehicle passes on the road on the concrete floor slab 202 act, the space holding material 2 and the filler 3 do not deform, and the road surface height can be maintained at the height before the hunch part 204 is cut. And since these external forces are dispersed and acted on the entire main girder 201 through the filler 3, the concrete floor slab 202 is stably supported.

[0035] In this way, even when the hunch part 204 is cut into the upper half and the lower half by cutting and the main girder 201 and the concrete floor slab 202 are cut and separated, the synthetic structure 100 has the function of integrating them. Therefore, as shown in Fig. 3, in the range where the hunch part 204 is cut. By forming the synthetic structure 100 provided with the shear key structure 1, the cut and separated concrete floor slab 202 can be recombined with the main girder 201, and the bridge 200 can function as a composite girder bridge.

[0036] Thereby, even during the period from the operation of cutting the hunch part 204 and separating the concrete floor slab 202 and the main girder 201 as described with reference to Fig. 1 to the start of the operation of forming a plurality of floor slab pieces 205 to remove the concrete floor slab 202, general vehicles can be used on the road of the recombined bridge 200 without imposing restrictions on the running load or regulations on the running lane.

[0037] ≪Method for Re - synthesizing Main Girder and Concrete Floor Slab≫ Next, a method for re - synthesizing the main girder 201 and the concrete floor slab 202 to re - synthesize the cut - off and separated concrete floor slab 202 to the main girder 201 in a desired section will be described below.

[0038] <Process of Cutting Haunch Portion> First, as shown in Fig. 5(a), the haunch portion 204 is cut along the upper surface of the main girder 201 in the bridge axis direction to separate the main girder 201 and the concrete floor slab 202.

[0039] The cutting operation is temporarily interrupted when a randomly set distance is exceeded. Since the stud dowel 201c provided on the upper surface of the main girder 201 is embedded in the concrete in the haunch portion 204, this stud dowel 201c is also cut simultaneously.

[0040] For cutting the haunch portion 204, any construction method may be adopted as long as the concrete and the stud dowel 201c constituting the haunch portion 204 can be cut together. In this embodiment, a push - cut method using a wire saw is adopted, and the haunch portion 204 is sequentially cut in the bridge axis direction. When cutting the haunch portion 204 along the bridge axis direction using a wire saw, for example, a cutting device 300 as shown in Fig. 6 may be adopted.

[0041] As shown in Fig. 6, the cutting device 300 includes driven pulleys 301 and 302 that are paired with each other across the main girder 201, and a wire saw 303 wound around the driven pulleys. The driven pulleys 301 and 302 are provided in an erected posture that rotates in a direction intersecting the upper flange 201a of the main girder 201. Further, the driven pulleys 301 and 302 are freely supported for movement in the height direction of the haunch portion 204.

[0042] Adopt such a cutting device 300, and while running the wire saw 303 wound around the driven pulleys 301 and 302 in the extending direction, press it against the planned cutting position of the hunch part 204. In this state, while moving the driven pulleys 301 and 302 along the main girder 201 in the bridge axis direction, periodically change the height position (in the height direction of the hunch part 204). By doing so, on the hunch part 204 after the wire saw 303 has passed, a cutting surface 204a on the side of the main girder 201 and a cutting surface 204b on the side of the concrete floor slab 202 with a wave shape that meshes with each other are formed.

[0043] <Step of filling the gap generated in the hunch part with a filler> Next, drive a pair of space holders 2 as shown in Fig. 5(b) into the gap between the cutting surface 204a on the side of the main girder 201 and the cutting surface 204b on the side of the concrete floor slab 202 formed in the hunch part 204 by cutting.

[0044] After that, as shown in Fig. 5(c), attach a sealing material 4 to the outer part of the gap between the cutting surface 204a on the side of the main girder 201 and the cutting surface 204b on the side of the concrete floor slab 202 to surround this gap. The sealing material 4 may adopt any one as long as it can block the space for filling the filler 5, and it may be removed after filling the filler 5 or may be left in place.

[0045] In this way, fill the gap surrounded by the sealing material 4 with the filler 5. The process of filling the filler 5 may be at any time after arranging the space holders 2.

[0046] Repeatedly perform the operation of cutting the above-mentioned hunch part 204 to form the shear key structure 1 and the operation of filling the filler 5. In this way, the synthetic structure 100 is provided in the desired section.

[0047] Thus, the shear key structure 1 that constitutes the composite structure 100 can be formed by cutting the hunch portion 204 in a waveform that intersects the bridge axis direction. Therefore, when re-combining the existing concrete floor slab 202 after cutting the hunch portion 204 with the main girder 201, the installation work of the composite jig, which was conventionally carried out, can be omitted, and the work efficiency can be significantly improved. Note that the cross-section of the main girder 201 may be an I-shaped or box-shaped.

[0048] The composite structure 100 of the main girder 201 and the concrete floor slab 202 of the present invention, and the method of re-combining the main girder 201 and the concrete floor slab 202 are not limited to the above-described embodiment, and various modifications are possible without departing from the spirit of the present invention.

[0049] For example, a structure in which the shear key structure 1 and the filler 5 are provided in the composite structure 100 was exemplified. However, when the shortage of the horizontal shear force in the bridge axis direction, which was borne by the anti-slip such as the stud dibel 201c provided on the upper surface of the main girder 201, generated by cutting the hunch portion 204, can be ensured only by the adhesive force of the filler 5 and the frictional force due to the self-weight of the floor slab, only the filler 5 may be filled between the cutting surface 204a on the main girder 201 side and the cutting surface 204b on the concrete floor slab 202 side, and the shear key structure 10 may be omitted.

[0050] Also, in the present embodiment, when cutting the hunch portion 204, a shear key structure 1 having a waveform shape in which the cutting surface 204a on the main girder 201 side and the cutting surface 204b on the concrete floor slab 202 side mesh with each other was formed by cutting in a waveform shape. However, if a shear key structure 1 can be formed between the cutting surfaces 204a and 204b, other methods may be adopted.

[0051] And the method of re-combining the main girder 201 and the concrete floor slab 202 in the present embodiment is applicable to both the method of replacing the entire cross-section (the entire cross-sectional surface) of the concrete floor slab 202 and the semi-section floor slab replacement method of replacing the semi-section.

[0052] The half-section floor slab replacement method is, for example, a method in which traffic lane regulation is carried out on a two-lane-up bridge 200, and one half-section of either the driving lane side or the passing lane side in the concrete floor slab 202 is replaced with a newly constructed concrete floor slab, and subsequently, the other half-section is also replaced with a newly constructed concrete floor slab in the same manner.

Description of Reference Numerals

[0053] 100 Composite Structure 1 Shear Key Structure 2 Space Retaining Material 3 Filling Material 4 Sealing Material 200 Bridge 201 Main Girder 201a Upper Flange 201b Web 201c Stud Girder 202 Concrete Floor Slab 203 Counter Inclination Structure 204 Hunch Part (Joint Part) 204a Cutting Surface (Main Girder Side) 204b Cutting Surface (Concrete Floor Slab Side) 205 Floor Slab Piece 300 Cutting Device 301 Driven Pulley 302 Driven Pulley 303 Wire Saw

Claims

1. A composite structure of a main girder and a concrete floor slab of a bridge, which recombines the concrete floor slab of the bridge separated from the main girder by cutting the joint portion back to the main girder, A composite structure of a main girder and a concrete floor slab, characterized in that a shear key structure and a filler are provided between the cutting surface on the main girder side and the cutting surface on the concrete floor slab side at the joint portion.

2. In the composite structure of a main girder and a concrete floor slab according to Claim 1, A composite structure of a main girder and a concrete floor slab, characterized in that the cutting surface on the main girder side and the cutting surface on the concrete floor slab side are formed in a wave shape that meshes with each other to form the shear key structure.

3. In the composite structure of a main girder and a concrete floor slab according to Claim 2, A composite structure of a main girder and a concrete floor slab, characterized in that the wavelength of the wave shape is about 3 to 10 times the amplitude.

4. In the composite structure of a main girder and a concrete floor slab according to Claim 1, A composite structure of a main girder and a concrete floor slab, characterized in that only a filler is provided between the cutting surface on the main girder side and the cutting surface on the concrete floor slab side, instead of a combination of the shear key structure and the filler.

5. A recombining method of a main girder and a concrete floor slab of a bridge, which recombines the concrete floor slab of the bridge separated from the main girder by cutting the joint portion back to the main girder, A method for recombining a main girder and a concrete floor slab, comprising the steps of cutting the joint portion so that the cutting surface on the main girder side and the cutting surface on the concrete floor slab side have a wave shape, and filling a filler between the cutting surface on the main girder side and the cutting surface on the concrete floor slab side.

Images